Simple Techniques for Lowering the Cost of Zero-Energy Homes
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A carbon tax would go a long way to solving this by giving people correct price information so they can make good decisions. If energy was more expensive people would demand more energy efficient homes.
Having bought a number of homes it's surprisingly painful and infeasible to compare apples-to-apples upfront. "Easy" to get details on a per-house level but just about impossible to filter your search early based on efficiency.
http://www.adene.pt/sites/default/files/documentos/certifica... (PDF)
Companies that perform this certification lobbied to make it mandatory whenever selling a house. However, the certificate does not tell you the real energy consumption. The calculation is based on "weighting factors" for whatever energy production format the politicians want to favor currently, so at least where I live, in Finland - where energy consumption really matters in the winter - when you buy a house, you pay for a certificate that is not very useful, and then you ask the previous owner for the actual energy bills he had, to asses the real cost and consumption.
The latter is, of course, what everyone did already before this certificate system.
OK, it's just a few hundred euros per sale. A bigger problem in the various energy saving initiatives is that houses built to this code sometimes develop very nasty air quality problems (due to air not changing in some places fast enough, or subtle leakages in the airtight balloon where you live) which then forces costly renovations and in the worst case destroy health.
Not sure if YT links are OK but check out Matt Risinger Blower Door Test
Energy Star: https://www.energystar.gov/newhomes/
Zero Energy Ready Homes: https://energy.gov/eere/buildings/zero-energy-ready-home
Passive House: http://www.phius.org/home-page
LEED for Homes: https://www.usgbc.org/cert-guide/homes
And my favorite, the Pretty Good House: http://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/p...
Honestly, if you're buying a new home and the builder hasn't ponied up for Energy Star, you've got to wonder where their priorities are - it's not a difficult program to achieve. You can find Energy Star builders here: https://www.energystar.gov/index.cfm?fuseaction=new_homes_pa...
I agree, there is little transparency on the home-buying front, largely because adherence to one of these certifications is still pretty rare. Also, it's rarely taken into account in the appraisal process.
22% of homes received HERS Index Scores in 2016. It is a simple score that indicates the efficiency of a home. A score of 0 represents Net-Zero, and score of 100 represents a "typical home". If you're buying a home (and you care), you should ask if it has been HERS Rated and to see the HERS Certificate.
Source for 22%: http://www.resnet.us/blog/national-renewable-energy-laborato...
Utility bills or estimated utility bills are the clearest way we have found to advertise the value to renters.
LED lights pay for themselves in a few months if you get a good price on-line or from a home center.
Added attic insulation is another thing that will pay for itself in a few months DIY, or a few years if you pay to have it done.
BuildItSolar has a slightly dated but still useful section about cutting your energy use in half at: http://builditsolar.com/References/Half/Half.htm
Getting insulation into walls is hard and at some point doesn't help a lot if there are air gaps.
New mechanical systems aren't really cost effective (because operating costs aren't that high; hundreds of dollars of monthly savings on a $10,000 upgrade). For people that use a lot of cooling replacing an old air conditioner can be a big win.
A good building is considered one if it has proper thermal design, and definitely commands higher price.
In this country, some provinces spend 1/3 of their GDP on energy.
Here, buildings with 30cm+ insulation and triple glazed, metalised, air-tight windows are not rare.
People should still build energy efficient dwellings, but there is no energy price spike around the corner (for electricity at least).
An hour of sunlight on Earth supplies enough energy to power humanity for a year.
Increases in electricity prices can definitely happen.
That said, most people who have never even started optimizing their house can find things that will payback in months, where it definitely is worth it.
Example: When I moved into this house about 8 years ago, every single light in the place was incandescent, and every fixture that could take multiple bulbs had them all full. The house was IMHO actually painfully bright, and that via incandescents. There was an easy win there even 8 years ago with CFLs, and it's only gotten better since.
(Do you really need 4 80-watt unfrosted (!) incandescent bulbs over your bathroom mirror? I sincerely hope somebody just slapped them there to make the house look "better" for the sale by not having empty sockets there being unsightly. I've got one 14W CFL in there and that's plenty of light.)
However, no, 4x80W bulbs aren't needed. When someone does need to do makeup, replace them with 4 1200 lumen 5000K bulbs (15-17W each).
Yes, you can create asset bubbles in the stock market and real estate. But the cost of everything else (besides RE, equities, health care, and education) is going down. The cost of energy will continue to decline, because we are awash in renewable energy, and the collection mechanisms are technology that continues to decline in cost precipitously.
[1] https://www.bloomberg.com/news/articles/2017-08-16/fed-minut...
Remember, the FED can make unlimited cash just show up so they have unlimited leverage. They are simply cautious.
Here's an article that talks about this unfortunate disconnect: http://www.finehomebuilding.com/2017/04/26/dont-build-better...
If people are burning more gas than they need to that's less money for them to spend on everything else. It's like the whole country living on credit card debt and not worrying about the interest because it's in the future. It's making you literally poorer and giving you nothing in return, just due to a lack of foresight and planning.
Only it doesn't work that way.
The deal with the builder has traditionally been (only an example):
1) you pay upfront US$ 40,000 more for the construction of the house in an energy efficient manner
2) we promise you that this will allow you to save US$ 3,000 per year in energy
3) for whatever reasons the savings actualy result in US$ 2,000 per year instead, but that is "normal" and within the expected calculation error, and anyway we already got the additional US$ 40,000, sue us.
4) part of the added US$ 40,000 go in part (heating, cooling, ventilation, windows) that require some added maintenance costs and that won't anyway last 20 years and/or will have higher replacement costs.
5) also consider how the "savings" are dependent on actually living in the house, if you - say - go six months away closing the house, you won't spend anything for energy, while you will be paying anyway the added US$ 40,000 on your mortgage payment, same thing if you rent it, the people living in the house will get the savings, you will still be paying the same.
2- ok.
3- The savings can be much greater than that. Insulation alone has an amazing bang for the buck. And its passive.
4- Added maintenance for windows? They don't require a diamond polisher to be cleaned. Who replaces their windows and doors every 20 years? What specifically needs extra maintenance?
5- Even if you are not living in the house, you can capture a higher profit margin by including utilities in the rental price, or marketing it as an energy efficient house. This is a real edge case though. Interest rates are about 3.5% now. Even in your inflated cost estimate, that translates to $700 in interest for 6 months. Not exactly game changing IMHO.
You are also missing an important point- energy efficient houses also tend to be a lot more comfortable, there are less drafts, less swings in temperature, less affected by outside noise. And you get the satisfaction of not having to care so much if energy prices increase.
Do modern windows even last that long? From observation of my own and relatives' houses, and from looking at houses when buying, most lose their seal by 15-20 years—so, efficiency goes way down because the gap between the panes is breached, they fog and collect moisture, et c. Replacing is so cheap that even minor problems aren't considered for repair, as labor's similar either way.
"I could charge you $400 to fix this, or $500 to replace it, and the newer ones are slightly more energy efficient, and this one'll probably develop more problems soonish. UV/IR coating on this is torn up anyway, those things rarely last more than a few years, especially with young kids or pets, kind of a joke. Give you a deal—say, $2250—if you just wanna do all 5 on this side of the house so they don't look different, and to get ahead of problems on the others". That kind of thing.
It was only an example from experience, anecdata if you prefer, of course it depends on a lot of factors, besides size of the house and country where it is built, it also depends on what is the current "base level" (coming from either local regulations or "common uses") from which you start.
In EU there are levels for houses from G (worst) up to A (and then a few better ones A+ and A++) very similar to the more generic EU Energy Label:
https://en.wikipedia.org/wiki/European_Union_energy_label
Since 2010:
http://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELE...
And the construction of new buildings have progressively shifted since 2010 from a "minimum acceptable" of Class C to currently Class A and soon Class A+ and A++, here is a good sum up:
http://gildera.com/timber-frame-homes/low-energy-house/
>3- The savings can be much greater than that. Insulation alone has an amazing bang for the buck. And its passive.
But they can be also much less, it was just an example, it depends on country, size of the house, costs of energy, etc., etc.
>4- Added maintenance for windows? They don't require a diamond polisher to be cleaned. Who replaces their windows and doors every 20 years? What specifically needs extra maintenance?
Essentially locking systems and seals/gaskets.
Also hinges (or rolling sets), modern double/triple glass is thick and very heavy and put extra stress on hinges or - in the case of sliding windows/doors to the rollers.
Understandably everything fits with very small clearances and it is not uncommon to have to register (besides lubricating) hinges, locks (and/or rollers) once a year.
Depending specifically on the way the window were installed there may be some sealing that needs to be replaced every 5 years or so.
Double/triple glass have one or more "air chambers" that are actually pressure filled with "noble gases", usually Argon or Kripton, and then sealed.
It is not uncommon (particularly on windows subject to extreme temperature stress) that in 10, 15 or 20 years time the sealing lets the noble gas out and some air (and moisture) enters the air chamber.
>5- Even if you are not living in the house, you can capture a higher profit margin by including utilities in the rental price, or marketing it as an energy efficient house. This is a real edge case though. Interest rates are about 3.5% now. Even in your inflated cost estimate, that translates to $700 in interest for 6 months. Not exactly game changing IMHO.
Again it greatly depends on country, etc., etc. but the point was only about the fact that energy saving not necessarily means money savings, as a matter of fact till now the energy saving (good) came with an initial increase of the construction costs that not necessarily you can recover.
>You are also missing an important point - energy efficient houses also tend to be a lot more comfortable, there are less drafts, less swings in temperature, less affected by outside noise. And you get the satisfaction of not having to care so much if energy prices increase.
Actually you are missing the point I was trying to make, a well built energy saving house can be a lot more comfortable, but - with some exception of course - very few houses are actually well built and when they are not well built they are besides uncomfortable also unealthy.
The problem is when you tell the customer that Spray Foam at 3" / per sq/ft costs approx $3 dollars (approx 16-20k to insulate a 3000 sq/ft home)they look at you like you raped their sister and killed their mother. Yet when you quote them a kitchen for 40k they smile and have no problems paying $140 a linear ft for counter tops or $10 a sq/ft for carpeting. Cosmetic items can be replaced at anytime (hardwood floors, tiles, kitchens, etc) but try to rip off all the drywall in your home to re-insulate or dig/drill up your property to install geo thermal.
People need to invest more into the mechanical structure of the home instead of the cosmetic details if they are serious about building an efficient dwelling. The building code at all levels needs to reflect a higher level of efficiency and government programs in the form of tax credits should be used to promote these upgrades and it would go a long way in helping reduce emissions.
I keep telling people that Spray Foam and Geo Thermal is free. It pays for itself rather quickly while providing a comfortable environment to live in.
However, spray foam also doesn't address wood-to-wood contact areas where air leakage can occur. The best air-sealing results are typically achieved with a taped exterior sheathing layer, or a taped sheet membrane (located on the interior, exterior, or mid-wall). The most common air-sealing method that works is the use of Huber Zip panels with Zip taped seams (or another quality acrylic tape). One caveat - I say most common because it is a very common material, but that doesn't mean the correct air-sealing methods are always used.
[0]http://www.greenbuildingadvisor.com/articles/dept/musings/ai...
A modern day house when built and finished has approx 2000 ft of linear cracks in it. It is the equivalent of keeping your front door open all year around. There have been test cases done where two homes are built exactly the same but the insulation in one of them is spray-foam. They then do a blown door test and the results speak for themselves. The spray-foamed house has almost no leakage.
Here is a couple great sites for anyone in NA to learn more about spray-foam. Demelic is based in Grand Prairie TX and in my opinion makes excellent foam. BASF is another great foam also.
The reason I advocate against spray foam is that contractors are terrible on the whole. They do the bare minimum. So I don't expect them to treat the foam. Take hardi siding. You're supposed to flash behind ever joint. Most don't. So now you get water infiltration. Then you go to Hardi. They won't stand by the warranty because of improper installation.
http://www.industrialproducts.com/industrial_products_blog/d...
The drywall is the only barrier you need since it is the fire proofing for all your framing and insulation. Only when the spray foam is not protected is there a need to cover it with fireproofing. If it is in a location where there is no open flame then fire retardant is not necessary.
Please educate yourself about spray foam from the following links.
>The reason I advocate against spray foam is that contractors are terrible on the whole.
I hope your advocating against all insulation because installing Fiberglass Bat Insulation is done improperly also. How accurate is the blown in insulation in the attic? We could advocate in not building houses at all because contractors are terrible on the whole. Maybe you should advocate that the consumer educate themselves so they understand what the difference between a good job and a bad job is.
The biggest problem with contractors these days are people want to pay as little as possible. The contractor therefore has to cut corners (do the bare minimum)to make the job profitable which can lead to problems down the road where you might not have the R-Value you expected. When you nickle and dime people trying to make a living the results can be less than optimal and that goes for any industry.
The benefits of spray foam are many, it can increase the structural integrity of a framed wall %200, mold and mildew free, not a food source for bugs or animals, better R-Value than traditional batting insulation or blown in and best of all it pays for itself and can significantly reduce your energy bill from DAY 1.
So in a typical house you've got a temperature of 68F in the duct, surrounded by 150-160F temps. R-4 insulation doesn't help much in that situation. But if they roof were insulated the attic space temperature would be in the 80's, so you'd only have about a 20 degree difference and R-4 could handle that.
A building needs to be designed from ground up for efficiency
Then it's unexotic stuff like making sure doors have decent seals on them. Double glazing is pricey and some way down the list.
Retrofitting better insulation to your walls if you don't have cavities is very expensive (you'll have to redecorate the house, too) but effective.
Good triple-glazed windows are expensive, but there are some vinyl triple systems that are reasonably priced. Anderson and Pella both have triple glazed options, for example.
There is also a relatively inexpensive (compared to imported European windows) option for tilt-turn windows now available: http://logicwd.com/
I haven't installed them myself, but I've bought other systems from that vendor and have been happy.
Internationally speaking, the UK is very far behind when it comes to insulation. Single glazed windows are still standard in many houses. Energy prices are cheap compared to the rest of the continent and costs are still one of the highest.
The gaskets maintain an airspace between the glass panes, which is responsible for most of the thermal performance. On new windows this can even be filled with a transparent gas (like argon or krypton) to increase performance.
Although, in certain districts in San Francisco, London, and New York the average land-to-building ratio is near 90%.
Sort on the land share column on this data sheet, and you'll see that SF is near that. Don't have data offhand for London, but given the reporting on it, it actually seems higher.
https://datatoolkits.lincolninst.edu/subcenters/land-values/...
In an RV if you're cooking or venting in the shower the directions pretty clearly say something to the effect of "open a window"—those things are sealed pretty tight and the air you're pushing out needs to be replaced with something...
So when you are taking a shower and use a ceiling vent (louvered, I assume) where does the replacement air come from if you're sealing up the house? Otherwise you'd just be creating a pressure difference and the fan wouldn't be moving a lot of air. What am I missing?
Very tight homes may need air inlets (literally fancy holes in the wall somewhere), or a balanced ventilator system. Appliances that can draft are also an issue. Some are generally discouraged, like drafting water heaters, and some will require their own air inlet, like wood burning fireplaces.
"2011 Ventilation Guide" by Armin Rudd is a very readable introduction to this subject. https://buildingscience.com/bookstore/books/2011-ventilation...
For online reading, here is a very short introduction: http://www.greenbuildingadvisor.com/green-basics/ventilation...
Here is a longer discussion: http://www.greenbuildingadvisor.com/blogs/dept/musings/desig...
The warm moist outgoing air gives up some of its energy to warm the incoming air.
Set aside for one moment the vapour from the shower, and from either the dryer or coming from the natular drying of washed clothes, there is the human generated vapour and that created by cooking.
In modern houses (without an efficient ventilation system) the airtightness causes condensation/moisture (usually in corners of the rooms or wherever there is a thermal bridge) which usually evolves in this (or that) form of mould or mildew.
Some (not all) heat insulation materials make the walls (besides airtight) also watertight, which makes the issue worse.
The idea of creating openings to allow the air in, which may be good in - say - a kitchen where the air also exits normally via the extractor hood or chimney (at the cost of some energy/heating/cooling dispersion) does not work in other rooms, where the openings most of the time either do not guarantee the circulation of air or behave as "heat dispersion" holes, negating all the savings that the airtightedness gave you.
Not only, people breath and emits, beside vapour, C02.
I know that it sounds obvious, but if you don't let (fresh) air in, before or later you will find yourself in a low-oxygen environment.
Having "normal", not airtight, windows and doors makes continuous ventilation of the interior of the house a "natural" phenomenon (with a cost in energy).
If you make an "airtight" house, additionally "watertight" (as an example using polystirene or similar for heat insulation) you are essentially living in a unhealthy environment, unless you provide a suitable ventilation system, and a ventilation system without an air-to-air exchange (to re-use part of the heath or cold) will negate most of the saving effects of the added insulation/airtightedness.
So, as pointed out by PoachedSausage, heat recovery ventilation is an actual need in energy saving houses, but it is still rather uncommon.
Of course keep the power places you need it, like the kitchen, bathroom, or entertainment center.
That said, I think there is a role for an additional low voltage power system in dwellings. But it would run alongside the existing system just like POTS, CAT5, and coax because that makes it practical to upgrade existing buildings.
What is missing is a standard, but USB C seems to be heading that direction. The problem with USB C currently is that of all standards, there are so many USB C's to choose from.
[1]: http://www.fireengineering.com/content/dam/fe/online-article...
For actual power tools well.. I help my kids like indoor biking :heh:
If the famous vacuum cleaner repairman Reddit AMA is to be believed, the overwhelming majority of vacuums purchased are so in name only, producing far too weak a vacuum to do any good and relying on carpet-damaging powerful brushes to do the cleaning. So we don't even have working light-ish vacuums, let alone low-power ones, let alone affordable light and low power ones. The ones that actually do what they're supposed to are still heavy and expensive (and, I assume, power hungry).
GF has a German brand hoover I always forget that has insane suction.
Controllable suction, attachments that clip together with incredible precision, the thing feels put together rather than slapped together.
But back to the original topic, we don't really waste that much power with wall-warts and such. Better to look at refrigerators, clothes/dish washing, HVAC.
If I'm on my computer at night and just want to heat my room, why do I instead have to heat the entire house/apartment? What a waste!
I think this is still achievable using existing systems. Keep the central unit, but modify the air ducts to have programmable valves. Then you can choose which rooms to have the ducts open/closed to. Sure, there will see some loss, but much better than maintaining temp for the entire building.
[0] https://s26.postimg.org/6ewi90rk9/rooms-e1442847765216-1024x...
Plus the building is usually designed as a unit- the envelope is sealed and insulated, room-to-room is not at all.
So the heat or cool just one room strategy I think is only compelling in a poorly designed building.
Lots of houses in the US don't have central HVAC, and only non-central heating and non-central (or no) AC.
> But why can't I program my thermostat on a per room basis?
You can; system zoning [0] is a thing, even with central HVAC.
> I think this is still achievable using existing systems. Keep the central unit, but modify the air ducts to have programmable valves.
Yes, that's how the well-known and widely deployed (though not super-common in single-family homes, because of the up-front cost) technology works.
[1] http://zeroenergyproject.org/2017/07/24/simple-techniques-lo...
The house is also designed to use the "stack effect" to passively cool it in summer, though experience with it shows it could have been done better.
I didn't care too much to super seal air leaks, because of potential indoor air quality issues.
>> didn't care too much to super seal air leaks, because of potential indoor air quality issues.
The time of day that you want air flow varies with the season.
The thermal properties of compressed earth brick(CEB) make heating and cool a house a lot different. It would be interesting to see what the financial number are if CEB were used instead of modern stick housing.